With the increasingly fierce competition in the synthetic fiber market, it is important to operate at a high performance to cost ratio. This has been done before by: a) improving the fiber properties (performance) by the development of the dry jet wet-spinning of aramids (e.g., Kevlar™) or gel-spinning of polyethylene (e.g., Spectra™), or b) reducing the production cost via high-speed spinning in the melt-spinning process of thermoplastic polymers. Polyolefins, polyesters, and polyamide fibers have been typically produced using a melt-spinning or the melt spin-draw process. Efforts have been made to improve the fiber performance in this relatively inexpensive process, but the properties of the melt-spun fibers are typically much below those of the wet- or gel-spun fibers.
Melt-spun fibers, however, with physical properties that are comparable to those resulting from wet or gel spinning techniques, have been attempted, but with little success. These processes come with numerous expenses, for example, capital expenditure for appropriate polymer handling, plant space, manpower and storage facilities. Yet despite advances in polymer science to date, melt-spun fibers having a tenacity and modulus typical of, or even intermediate to, the tenacity and modulus of high performance fibers such as Kevlar™ or Spectra™ have not heretofore been obtained.